/Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Public/Widgets/SItemSelector.h
The default categories to show in additional to ones generated from the items. NOTE: The OnCompareCategoriesForEquality, and OnGenerateWidgetForCategory delegates must be bound if this argument is supplied.
WidgetArgsType & DefaultCategories &40; TArray< CategoryType > InArg &41;